@Gabe G. Congrats on the new properties and encourage you to keep going. Quickly using the 50% rule, $850/2 = $425 and there is no way your mortgage is $25. How are you coming up with the cash flows?
Suggestions that has helped us as a landlord: Walk through the entire lease agreement with your tenant to make sure they fully understand especially when/where rent is due and what is considered an emergency repair. Fire, flood and blood is an easy way to put it for them.
What @Jerry W. said about being patient on screening tenants is so true. If you have a clean and functional property and priced it right, you will find the right tenant.
If possible, try to incorporate your capital expenses into your numbers as you analyze the deal before submitting the offer. If the numbers work, you'll fix the needed major items (ie roof, water heater, AC) up front minimizing your maintenance calls down the line. If not, save aside capital expenditure for these items in case they crap out on you.
In the end, never stop learning, connect with others (adding a profile picture helps with this) and have fun along the way.